Marine organisms such as algae and barnacles attach to the surfaces of structures placed in oceans and lakes. This marine growth has little effect on the integrity of the structure such as ships, boats, pilings, water intake and outfall (coatings) pipes. (Worms and bores do attack woods and plastics.) However, their presence can seriously hamper the operation of these systems, resulting in loss of cooling and fuel efficiency. It has been common practice to coat the substrate surfaces of wood, plastic and metal with coating compositions which inhibit attachment and/or growth of marine organisms. Such coating compositions are usually referred to as antifoulant coatings or antifoulant paints and consist of a polymeric binder material, a toxicant, a pigment, solvents, and adjuvants to aid in adhesion, flow, color, viscosity, stability, etc. The range of compositions for marine antifoulant application is enormous and has evolved from changing needs. For example, 1-2 years protection was adequate for most ships which were dry-docked every 1 or 2 years for routine maintenance and were stripped and repainted with new antifoulants while in dry dock. With the advent of the super tanker, greatly extended intervals between dry docking were requiredxe2x80x94typically 3 to 5 years. Thus, the need for longer life antifoulant coatings was created. This need was in great measure met by the extended performance made possible by polymerizable antifoulants, such as organotin methacrylates, which became part of the coating polymeric binder. Improvements were also made by creating coatings which controlled erosion and toxicant leach rates to approach the 5 year life requirement.
In addition to extended life requirements for marine antifoulant coatings, concern for the possible effects of antifoulant toxicants on the environment has encouraged the development and use of systems which attempt to control fouling through surface modification; for example, prevention of attachment through the use of silicon or fluorine containing polymers having non-stick or release properties.
The development and current state of the art of marine antifoulant coatings can be found in articles such as:
1. Clean Hulls Without Poisons: Devising and testing non-toxic marine coatings. Robert F. Brady Jr., Coatings Technology, Vol. 72#900, January 2000.
2. A New Approach in the Development and Testing of Antifouling Paints Without Organotin Derivatives. K. Vullei Rehel, B. Mariette, P. Hoarau, P. Guerin, V. Longlois, J-Y. Longlois, Journal of Coatings Technology, Vol. 70, #880, May 1998.
3. Marine Biofouling And It""s Prevention on Underwater Surfaces. J. A. Lewis, Material Forum (1998), 22, 41-61.
Marine Antifoulants, Silcon/Fluorine
xe2x80x9cMarine Biofouling and it""s Prevention on Underwater Surfacesxe2x80x9d, by Lewis, J. A., Materials Forum, (1998) 22, 41-61, is a recent comprehensive review of marine antifoulant agents. An extensive bibliography and references are included. This paper makes reference to binders studied such as acrylic copolymers with pendant hydrolysable functions and a variable hydrophobic/hydrophilic balance. Reference #45 from which this description is taken is a thesis in French, by Fadel, A.xe2x80x94Thesis Universite de Rennes I, xe2x80x9cSynthesis et Application de Resines Erodable pour Peintures Antisalissures de Nouvelle Generationxe2x80x9d, 1994. This reference does not disclose the compositions of the present invention.
WO, 0014166A1, Judith Stein, General Electric Co., 2000, 03,16 describes curable silicone foul free release coatings and articles. No fluoro compounds are present.
xe2x80x9cSilicone Containing Fluropolymer Coatings Composition for Controlled Release of Organic Leachantsxe2x80x9d. James Griffith, Stephen Snyder, U.S. patent application Ser. No. 921054A0. This patent application discloses the use of fluoro-epoxy compounds and silicone amine curing agents rather than fluoro(meth)acrylates and silyl(meth)acrylate monomers to produce marine antifoulant binders. The resultant copolymers of Griffith are highly crosslinked.
JP 53113014, 19781003. Tachida, Toshij, xe2x80x9cMaterial for the Prevention of Adhesion of Organisms in Waterxe2x80x9d. Release coating as antifoulants are prepared from fluorinated polymers, above, e.g. polytetrafluorethylene. No silicon is present.
Additional antifoulant release coatings are described in the following patents and patent applications, none of which describes the compositions of the instant invention: U.S. Ser. No. 251419A0xe2x80x94application, U.S. Ser. No. 92847401xe2x80x94application, DE 2752773, EP 874032A2, EP 885938A2, JP 0319073A2, JP 319074A2, JP 04217902A2, JP 04227770A, JP 04264168A2, JP 04264169A2, JP 04264170A2, JP 070033191A, JP 07138504A2, JP 11061002A2, JP 61097374A2.
Further information on antifouling release coatings may be found in the following articles: xe2x80x9cThe Antifouling Potential of Silicone Elastomer Polymersxe2x80x9d, Clarkson, Nancy. Recent Advance Marine Biotechnol (1999) 3, 87-108; xe2x80x9cSynthesis of Perfluorinated Acrylate and Methacrylate Fouling Release Polymersxe2x80x9d, Arios, E M, Putnam, M. et al. Book of Abstracts 213th ACS National Meeting, San Francisco, Apr. 13-17, 1997; and xe2x80x9cFluoropolymers and Silicone Fouling Release Coatingsxe2x80x9d, Bultman, J. D., Griffith, James R., Recent Developments in Biofoulingxe2x80x94Control, 1994, 383-9.
Self Polishing antifoulant paints are described in several patent and patent applications such as: EP 51930A2xe2x80x94Marine Paint, International Paint Co., Ltd. Sghlbontz, C M. Which describes self-polishing marine paints comprising a copolymer methacrylate, methylmethacrylate and a organotin monomer.
Hydrophobic/hydrophilic polymers for use in marine antifoulant paints have been described in the prior art.
xe2x80x9cGraft Copolymers for Erodible Resins, from Alpha-Hydroxyacid Oligomer Macromonomers and Acrylic Monomersxe2x80x9d, Vallae, Rehel, et alxe2x80x94J. Environmental Polymer Degradation (1999) 71 (1) 27-34. This article discusses the compositions with defined hydrophobic/hydrophilic balance, but differs from the present invention in the use of alpha-methacryloryloxy-alpha-hydrox acid macromonomers.
Konstandt, Felix. FR 2165881, discloses a solution of polyethylenimine or its hydrophilic derivatives with a hydrophilic acrylic polymer for coating boats below the water line. This compositions differs from the instant invention in that it lacks any fluoro-containing compounds.
EP 0801117A2xe2x80x94Haradaa, A., Contains hydrophobic and hydrophilic groups but does not contain the monomers of the instant invention.
JP 5214274Axe2x80x94Komazaki Shigeru et al.xe2x80x94Contains hydrophilic and hydrophobic groups but based on N-acrylic imidazole modifications.
U.S. Pat. No. 4,883,852, Shigeru, Masuoka, Hiroshi Dor, Nippon Oil and Fats Co., 1989, describes and claims marine antifouling paints which contain a polysiloxane polymer and a copolymer which may be methacrylate ester/polysiloxane polymer.
U.S. Pat. No. 5,767,171, Matrubara, Yoskisa et al. NOF Comp., 1995 Contains silylacrylates. Describes and claims marine antifoulant coatings containing copolymers of monomers which contain an acryloyloxy or methacryloyloxy group and triorganosilyl group. A third vinyl monomer may be present. Does not disclose a fluoro-containing moiety.
U.S. Pat. No. 4,593,055, Melvin Gitlitz et al, MandT Chemicals (1986). Describes erodible ship bottom paints for controlling marine fouling which are characterized by including a hydrolysable organosilylacrylic copolymer. No fluoro-monomer is disclosed.
Surface Coatings International (1999), 82 (12) Bready R F for et al. describes waterborne fluoropolymer coatings for marine fouling resistance.
JP 05186715A2xe2x80x94Kido, Koichiro et al, 1993, describes marine antifoulant coatings which may contain acrylates and methacrylates as well as 2,2,2-trifluoro ethylacrylates, but it does not describe the presence of hydrolysable silylacrylate groups.
JP 61097374A2, Fuyuki, Toro et al, 1986. Paint additives for marine structures are prepared by copolymerizing fluoroethyl monomers and (meth)acrylates. No silylacrylates are listed.
xe2x80x9cFluorinated Polymer, Synthesis Properties and Applicationxe2x80x9d, Ameduri, Bruno et al. Actual Chemi (2000), (2) 23-32, discusses the synthesis, properties and applications of fluorinated polymers.
U.S. Pat. No. 4,410,363xe2x80x94Robert Supcoe, et al, 1983 Marine Antifouling Paint Containing Fluorinated Waxes.
2,2,2-Trifluoroethylmethacrylate (matrife) is one of the monomers used in the marine antifoulant coatings of the instant invention. Matrife has been used in applications other than marine paints. Examples include: WO 9905548A1xe2x80x94Yamashita, Tomoyou (Mitsubishi Rayon) 1999, Graded Index Plastic Optical Fiber; WO 9125962A1xe2x80x94Imafuku, Sujuru et al, 1996. Copolymers for the production of soft intra-occular lenses;
JP 8134381xe2x80x94Yamashita Tatashi et al, 1998. Toray Industrial. This patent claims an antifouling method characterized in that it has a composition that contains a copolymer obtained by polymerizing as essential components: 50 to 99 weight percent of a fluorine containing polymerizable monomer and 1 to 50% of a compound having at least 1 hydrolysable silyl group per molecule and that contains an organo-polysiloxane that has reactivity with the hydrolysable silyl group in its side claim and/or terminal. However, the Japanese patent differs from the instant invention in significant ways, such as the hydrolysable silylacrylate has pendant reactive groups, for example, tri alkoxy silylacrylate versus alkyl silylacrylate in the instant invention. The alkoxy silylacrylate form will react with a substituted polysiloxane while the trialkylsilylacrylate will not.
Antifoulant paints containing both fluoro and silylacrylate groups are disclosed in several patents: JP 8134381, Yamashita, Jotoshi et al, 1998, Toray Industries, as noted in above, discloses a binder and a toxicant for marine paint, the binder comprising a (meth) acrylate copolymer which has been substituted with a hydrolysable silylacrylate group copolymerized with a fluoro (meth) acrylate monomer and a polysiloxane. However, it is apparent that the silyl acrylate group can be hydrolyzed both at the acrylate silicon substituent and at the other silicon substituent sites since these sites are alkoxy groups; thus, hydrolysis of more than one silicon substituent would result in extensive crosslinking between the binder backbone and the polysiloxane additives. The silicon substituents of the present invention other than the acrylate functionality are based on non-hydrolysable alkyl groups. Thus, crosslinking through the polysiloxane additive would be minimal, if at all.
U.S. Pat. No. 5,912,286, Griffith, James R. et al 1997. A fluoro-epoxy compound and a silicone amine curing agent comprising a polymer matrix for a binder of a leachable organic compound for us in marine antifouling coatings.
The present invention provides improved polymers useful as binders in self polishing marine antifoulant paints and the resulting marine antifoulant paint containing the polymer. The new polymers are made from at least three distinct monomers units selected from the group consisting of fluorinated acrylic monomers, (e.g. 2,2,2-Trifluoroethylmethacrylate (matrife)), triorganosilylacrylic monomers, (e.g.trimethylsilyl methacrylate) and acrylic monomers not containing an organosilyl moiety, (e.g. methyl methacrylate). The three component polymer (i.e. terpolymer) can optionally contain from 0-5 weight percent of a cross-linking agent. The terpolymers are novel compositions useful as polymeric binders in long life marine antifoulant coatings. The erosion rate and resistance to cracking of the polymer of the present invention when used as a binder in a marine antifoulant paint is controlled by adjusting the proportions of each monomer and the amount of cross-linking agent in the copolymer. The polymer of the present invention is a copolymer comprising the reaction product of:
a. a monomer of the formula: 
wherein R is CH3 or H, and RF is (C)u(CH)v(CH2)w(CF)x(CF2)y(CF3)z where u is from 0 to 1, v is from 0 to 1, w is from 0 to 20, x is from 0 to 1, y is from 0 to 20, z is from 1 to 3, and the sum of w and y is from 0 to 20,
b. a monomer of the formula: 
xe2x80x83wherein R is CH3 or H, and R1 alkyl or aryl, and
c. a monomer of the formula: 
wherein R is CH3 or H, and R1, R2, and R3 can be the same or different and are non-hydrolysable alkyl groups containing from 1 to 20 carbon atoms and/or non-hydrolysable aryl groups containing from 6 to 20 carbon atoms.
Also provided are marine antifoulant paints containing as a binder a copolymer of monomers a, b, and c as defined above.